1. Field of the Invention
The present invention relates to a printed circuit board with piezoelectric elements.
2. Description of the Related Art
In an electrophotographic image forming apparatus, for good image transfer to a sheet, a high voltage (a voltage of several hundred volts or more, which is higher than a commercial power supply voltage) is generally applied to a transfer roller, and a current of approximately 10 μA is applied to the transfer roller. To generate such a high voltage, conventionally a wound-rotor type electromagnetic transformer has been used. The wound-rotor type electromagnetic transformer is, however, difficult to reduce in size and weight. To further reduce the size and weight of an electronic apparatus such as an image forming apparatus, the size and weight of a power supply that generates a high voltage must be reduced. To achieve a reduction in the size and weight of a power supply, the use of a piezoelectric transformer (a piezoelectric ceramic configured as a transformer with electrodes) is being considered instead of using the wound-rotor type electromagnetic transformer. A piezoelectric transformer is capable of generating a high voltage with higher efficiency than the electromagnetic transformer and furthermore does not require molding for providing isolation between primary and secondary electrodes. Thus, the piezoelectric transformer brings the advantage that the power supply is reduced in size and weight (Japanese Patent Laid-Open No. 11-206113).